Add Warehouse and Inventory functions

[damiankw]

It would be good to have access to the Inventory, Stock on Hand, which requires access to Warehouses and Warehouse bins.

Examples:

Get-Warehouse Will list all of your warehouses, standard -options apply.

Get-WarehouseBin Will list all of your warehouse bins, standard -options apply.

Get-Inventory -parentId [WarehouseBinId] Will list all of your inventory in the Warehouse Bin as required by the API, standard -options apply.